Cooling arrangement for gas turbines



13, 1945- s. R. PUFFER 2,388,997

COOLING ARRANGEMENT FOR GAS TURBINES Filed June 28, 1939 Inventor: Samuel RFuff'er,

by r m afiwiq His Attorney.

Patented Nov. 13, 1945 UNITED STATES PA EN ARRANGEMENT FOR GAS TURBINES CQOLING T7 ori ce Samuel R. Pufier, Lynniield Cent er, Mass; assignor to General Electric Company, a corporation of New York Application June 28, 1939, Serial No. 281,576

2 Claims.

The present invention relates to cooling arrangements for gas turbines, particularly of the type of turbines which include a bucket wheel supported on an overhung shaft and having a row of buckets arranged to-discharge gases directly into the atmosphere. Such turbines are often used on aircraft for driving superchargers safely with gases at high temperatures of the order of 750 C. and above.

For a consideration of 'what I believe to be novel and my invention, attention is directed to stantially perpendicular'to the direction of the slip stream. The direction of discharge has been indicated in the drawing by an arrow 22 andthe direction of the slip stream has been indicated by an arrow 23. The latter in the present in stance is parallel to a diameter of the bucket wheel and perpendicular to the direction of discharge of gases, as well as to the axis of rotation foif the wheel. With reference to the direction of the slip stream, the upper portion ofthe bucket wheel It] in the drawing i leading and the lower portion of the bucket wheel is, trailing. In such the following description and the claims at.

pended thereto in connection with the accoinpanying drawing. g

In the drawing Fig. 1 illustrates a sectional view of a gas turbine arrangement-for aircraft embodying my invention, and Fig. 2 is a perspective view of a part of Fig. 1.

arrangement the slip stream forces gases issuing from the leading portion of the bucket wheel towards a central portion thereof and causes exces-- sive heating.

This diflicult i overcome in accordance with my invention by the provision of a device protecting and effectively cooling the bucket wheel disk. The device comprise a. cap 24 adjacent the outer face of the bucket wheel disk, and concave-shaped towards the latter. The cap is Y slightlysmaller in diameter thanthe maximum diameter of the rim. Similar cap are disclosed in the application of Chester W. Smith, Serial No.

281,562, filed-on the same date and assigned to the same assignee asthe present application, and since issued .as Patent No. 2,364,037. A portion The arrangement comprises an axial flow gas turbine with a solid bucket wheel Ill mounted on an overhung shaft ll adjacent a. bearing l2 of a supercharger I3.

The bucket wheel l0 has a disk with a rim It on which an annular row of buckets I5 is mounted. The outer ends of the buckets are connected by a band I ,6. An'annular nozzle box I! is mounted on one side of the bucket wheel and has an inlet portion l8 for, receiving gases from a suitable source, such as the exhaust manifold of a combustion engine, not shown. The nozzle box includes a row of nozzles l9 adjacent the buckets I 5 for properly directing operating gas to the bucket wheel. The nozzle box in the resent instance is mounted on studs 20 formed on the casing of the supercharger l3 by mean including a wall 2| which also serves to protect the bearing l2 from. heat radiated from the nozzle box l1. During operation high temperature gases are conducted from the nozzle box to one side of the bucket wh'eel passing through the passages formed between adjacent buckets and issuing from the other side of the bucket wheel directly into the atmosphere.

The bucket wheel is subject to the heat of the gases, as pointed out above, especially when the direction of discharge into the atmosphere is subof the cap is cut out to form an opening 25 and I a boxf-shaped structure 26 is secured to the cap,

preferably by fused metal, to circulate cooling air through the space 21 formed between the-cap and the bucket wheel. Thi box-shaped structure 28 forms an inlet 28 for-receiving cooling air. In the present instance the inlet 28 opens in the direction of the slip stream whereby the slip stream forces air into the space. The lower portion of the structure 26 forms an outlet 29 for discharging cooling air from the spac 21. The

box-shaped structure has an outer plane wall 30. In order to force the cooling air towards the central portion of the bucket wheel and properly toguide the air thereafter through theoutlet 29 a deflecting and guiding plate 3| is disposed inside thebox-shaped structure 26 and secured to. the walls thereof by means including flaps 32. During operation a continuous flow of cooling air through the structure 26 towards the bucket wheel takes place. .This air is forced into the inlet 28 by the relative motion of the air in the slip stream, and exhausted through the-outlet 29 by the downstream effect of the same slip stream. The outer rim of th cap 24 forms a relatively close clearance with the rim M of the bucket wheel so that little cooling air is discharged I thereof.

.2 through the clearance. This cooling air prevents entry or hot gases wheel, particularly As the discharge 0! cooling air through said clearance is small it does not appreciably interfere withthe tree discharge or gases from the bucket wheel. The cooling device is mounted on the nozzle bo'x H by means or brackets 33 and SI fastened to studs 35 and 38 respectively on the nozzle box [1.

what I claim as new and desire to secure by letters Patent 01 the United States is:

i. turbine arrangement for aircraft com prising a bucket wheel ior-directly discharging into the atmosphere and a device located on the discharge side of the wheel for cooling the central portion oi! the wheel, said device comprising a cap adjacent the wheel and having a riin forming a close clearance with the wheel, said cap having an opening, a box-shaped structure fastened to the cap around said opening and formassaeer discharged from the bucket near the leading portion be conducted to the space formed between the wheel and the cap and a discharge conduit tor discharging cooling air trom said space directly into the atmosphere with the discharge located substantially diametrically opposite the inlet.

2-. Gas turbine arrangement for aircraft comprising a bucket wheel, an annular nozzle box ing an inlet conduit for receiving cooling ainto located on one side Let the bucket wheel to conduct operating gas thereto, and a cooling device located on the other side or the bucket wheel and supported on the nozzle box, said device comprising a cap concave-shaped towards the wheel and forming a space therewith, a structure secured to the' cap and iorming inlet and outlet conduits for cooling air communicating with diametrically opposite portions of the space between the can and ms wall within the structure and secured tor the walls thereof for forcing cooling air entering the inlet conduit towards the wheel and guiding the air from said space'towards the outlet conduit.

SAMUEL R. PUFFER.

the wheel and a deflector and guidl 

